A conventional laser printing apparatus is configured to receive a stream of electronic data from a computing device and convert that data into an image on a recording medium, such as a piece of paper. The laser printer includes a laser that produces infrared wavelength light that is scanned back and forth across a photoreceptor drum with photoconductive material on the outer peripheral surface of the drum as the drum is rotated around a shaft. An electronic circuit in the printer determines how to print the data so that the information is presented properly on the paper. The electronic circuit of the laser printer activates a pre-charger, such as a corona wire or charged roller positioned adjacent to the rotating photoreceptor drum. The pre-charger donates static positive electrical charges developed by the corona wire, and the static electrical charges are discharged onto the photoconductive layer of the photoreceptor drum to create a positive charge spread uniformly across the surface of the drum. The electronic circuit of the laser printer also modulates the infrared wavelength light output from the laser in accordance with the stream of electronic data received by the laser printer. The beam of light produced by the laser is typically reflected off a rotary polygonal mirror driven in a back-and-forth manner by a motor to scan the reflected laser light beam across the photoconductive layer on the photoreceptor drum. The scanning laser light beam erases the positively pre-charged photoconductive layer in the areas exposed to the light, creating areas of negative charge on the photoconductive layer that correspond to the areas of an image that should receive black or other colors on the recording medium.
A developing means such as a toner-donating means donates positively charged toner particles on the photoconductive layer, and the areas of the photoconductive layer that have been exposed to the laser light beam are converted to negatively charged areas that attract and temporarily hold the positively charged toner particles. The recording medium, such as a sheet of paper, is then provided with a strong negative electrical charge, and passed adjacent to the photoreceptor drum. The negatively charged paper has a stronger negative charge than the negatively charged areas of the photoconductive layer, and hence attracts the positively charged toner particles away from the photoconductive layer on the photoreceptor drum and onto the surface of the sheet of paper to form the desired printed image on the paper.
Some of the disadvantages associated with using a rotating polygonal mirror to scan the laser light beam spot across the photoconductive layer on the photoreceptor drum include the noise associated with repeatedly rotating the mirror, and the wear and tear on the various control elements and moving parts associated with rotating the mirror. A non-mechanical method of scanning the light beam spot may alleviate these disadvantages.
The present disclosure is directed to overcoming one or more of the problems set forth above and/or other problems associated with conventional laser printing systems.